Defeat method and apparatus for content management for high definition television

• US 20060093139A1
• Filed: 10/25/2005
• Published: 05/04/2006
• Est. Priority Date: 10/28/2004
• Status: Abandoned Application

• Current Assignee: Macrovision Corporation (Adeia Inc.)
• Original Assignee: Macrovision Corporation (Adeia Inc.)
• Inventors: Quan, Ronald
• Application Number:
  US11/259,497
• Publication Number:
  US 20060093139A1
• Time in Patent Office: Days
• US Class Current: 380/201
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00753 wherein the usage restriction limits the number of copies that can be made, e.g. CGMS, SCMS, or CCI flags
• CPC Class Codes: H04N 2005/91314 the copy protection signal being a pulse signal inserted in blanking intervals of the video signal, e.g. pseudo-AGC pulses, pseudo-sync pulses
• CPC Class Codes: H04N 2005/91321 the copy protection signal being a copy protection control signal, e.g. a record inhibit signal
• CPC Class Codes: H04N 2005/91328 the copy protection signal being a copy management signal, e.g. a copy generation management signal [CGMS]
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 7/169 Systems operating in the time domain of the television signal

Abstract

A high definition television video content management and/or copy protection method and apparatus are achieved by modifying portions of one or more channels of an HDTV (high definition television) signal. These modifications are generally in the blanking intervals but can extend into the overscanned portions. In one version, the signal modification defines tags or trigger bits for a content control system. This modification may follow the HDTV tri-level sync (synchronization) pulses for example, and it may occur in at least one of the HDTV video channels. In another version, portions of the tri-level sync pulse are modified to cause a reference sensing circuit such an AGC system (in a receiving device such as a video recorder) to produce an erroneous output. Optionally, a signal may be added or inserted following the modified tri-level sync pulses. In another version, tri-level pseudo sync pulses are added in blanking or overscanned intervals. These tri-level pseudo sync pulses may be asymmetrical and may be followed by a signal. Further, any of the above modifications or signals or sync signals may be modulated (e.g., amplitude, position, pulse-width). Also provided are defeat methods and associated apparatus to reduce effects or to modify video signals resulting from the modification processes. The defeat methods include modifying a portion of the video signal associated with the tri-level synchronization pluses so as to allow subsequent recording of the modified video signal or to alter the information in the modified video signal pertaining to the content management such as the tags or trigger bits.

Claims

1. A method of modifying a video signal, comprising the acts of:

receiving a video signal generally conforming to a digital television standard and having tri-level synchronization pulses in blanking intervals of the video signal, wherein a portion of the video signal associated with the tri-level synchronization pulse has been earlier altered so as to inhibit recording of the video signal or to carry information relating to controlling use thereof, and

modifying the portion of the received video signal associated with at least the tri-level synchronization pulses so as to allow subsequent recording of the video signal or to alter the information relating to controlling the use thereof.

2. The method of claim 1, wherein the act of modifying includes modifying at least one of the tri-level synchronization pulses that has been earlier altered.

3. The method of claim 2, wherein the modifying occurs in at least one of the luma or chroma channels of the video signal.

4. The method of claim 2, wherein the act of modifying includes lowering or raising an amplitude of the back porch of the tri-level synchronization pulse to a reference level.

5. The method of claim 4, wherein the act of modifying includes raising the amplitude of the back porch from at least 20% below the peak white level of the video signal to the reference level.

6. The method of claim 4, wherein the act of modifying includes altering an amplitude of a portion of the tri-level synchronization pulse to render positive and negative going portions thereof symmetrical.

7. The method of claim 2, wherein the act of modifying includes altering at least one of a position, amplitude, or width of the earlier altered tri-level synchronization pulse to a reference level.

8. The method of claim 2, further comprising the act of modifying a plurality of the earlier altered tri-level synchronization pulses in the video signal, the alterations varying between different scan lines of the video signal.

9. The method of claim 1, wherein the act of modifying includes deleting or attenuating at least one pulse located in the blanking interval.

10. The method of claim 9, wherein the deleted or attenuated pulse extends into an active video portion of the video signal scan line prior to the deletion or attenuation thereof.

11. The method of claim 10 wherein the active video portion is an overscan portion of a field of the video signal.

12. The method of claim 9, wherein the act of modifying includes deleting or attenuating the pulse located in the blanking interval prior to or following a location of the tri-level synchronization pulses.

13. The method of claim 9, wherein the act of modifying includes deleting or attenuating the pulse from at least one of the luma or chroma channels of the video signal.

14. The method of claim 9, wherein the deleted or attenuated pulse has a portion which is positive or negative going prior to the deletion or attenuation thereof.

15. The method of claim 9, wherein the deleted or attenuated pulse has a configuration of the tri-level synchronization pulse prior to the deletion or attenuation thereof.

16. The method of claim 9, wherein the act of modifying includes deleting or attenuating a pulse located in a front or back porch portion of the tri-level synchronization pulse.

17. The method of claim 9, wherein the act of modifying includes deleting or attenuating a plurality of pulses located in the blanking interval.

18. The method of claim 9, wherein the act of modifying includes deleting or attenuating pulses located in a plurality of the blanking intervals, a character of the deleted or attenuated pulses varying between different of the scan lines of the video signal prior to the deletion or attenuation thereof.

19. The method of claim 18, wherein the character that varies is at least one of a position, amplitude, width, or number of the pulses.

20. The method of claim 9, wherein the deleted or attenuated pulse is a gray level pulse and is located in a back porch portion of the tri-level synchronization pulse prior to the deletion or attenuation thereof.

21. The method of claim 9, wherein the deleted or attenuated pulse has a duration one third to double that of the tri-level synchronization pulse prior to the deletion or attenuation thereof.

22. The method of claim 1, wherein the digital television standard is a high definition television (HDTV) standard.

23. The method of claim 1, wherein the standard is one of 720 line progressive scan (720p) or 1080 line interlaced (1080i) scan.

24. The method of claim 1, wherein the information in the received video signal at least in part defines a predetermined command for content management of the video signal.

25. The method of claim 1, wherein the inhibiting recording of the video signal is by causing a sensing system in an apparatus receiving the video signal to produce an erroneous output.

26. The method of claim 1, wherein the altered portion of the video signal is in at least two channels of the video signal.

27. The method of claim 26, wherein the alterations to the video signal differ between the two channels of the video signal.

28. The method of claim 1, wherein the alterations are in selected scan lines of the video signal in active video adjacent to the vertical blanking interval of the video signal.

29. Apparatus for modifying a video signal, comprising:

an input port adapted for receiving a video signal generally conforming to a digital television standard and having tri-level synchronization pulses in blanking intervals of the video signal, a portion of the video signal associated with the tri-level synchronization pulse having been earlier altered;

a processor coupled to the input port and modifying a portion of the received video signal associated with at least one tri-level synchronization pulse so as to allow subsequent recording of the video signal or to alter the information relating to controlling the use thereof; and

an output port coupled to the processor and adapted to output the modified video signal.

30. The apparatus of claim 29, wherein the modifying includes modifying at least one of the tri-level synchronization pulses that was earlier altered.